Metal Gate

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Metal Gate

In integrated circuits (ICs), conductive lines provide electrical interconnection among different parts of the ICs, devices, and the outside. The main applications of metallization are classified by gate, contact, and interconnection. Polysilicon and silicides are commonly applied as gates and interconnects in MOS devices. Aluminum, copper, tungsten, silver, titanium, platinum, gold, and palladium are used as these types of contacts, connections, and/or interconnection to external components.

Table 2049a shows the summary of 2003 Roadmap, listing the node, gate length, equivalent oxide thickness of high power (CPU) and low standby power devices (mobile), gate oxide material, and gate electrode material.

Table 2049a. Summary of 2003 Roadmap.

Year	2001	2003	2005	2007	2009	2012	2016	2018
Node	130	100	80	65	45	32	22	18
ASIC 1/2 pitch	150	107	80	65	45	32	25	18
Physical gate length	65	45	32	25	20	13	9	7
T_ox hi power	1.5	1.3	1.1	0.9	0.8	0.6	0.5	0.5
T_ox lo power		2.2	2.1	1.6	1.4	1.1	1.0	0.9
Gate oxide	Oxynitride			HfO_x; Si,N			LaAlO₃
Gate metal	Poly Si			Metal gate, e.g. TaSiN_x

Table 2049b. Metallization selections in ICs.

Application	Selection
Gates, interconnection, and contacts	Polysilicon, refractory metal silicides (e.g. MoSi_x, TaSi_x, WSi_x, and TiSi_x), nitrides,aluminum, copper, and/or refractory metals.
Diffusion barrier layer	Ti, TiN, Ta, TaN, Ti-W alloy, and/or silicides
Top level	Aluminum, and/or copper
Metallization on silicon	Silicides, tungsten, aluminum, and/or copper

Practical Electron Microscopy and Database

An Online Book, Second Edition by Dr. Yougui Liao (2006)

Metal Gate